1. Field of the Invention
The invention relates to a novel method for detecting tuberculosis and other infections in animals.
2. Description of the Prior Art
Cell-mediated immune responses are critical in the host defense against intracellular bacterial pathogens (Chan and Kaufmann, 1994, Immune mechanisms of protection, In Tuberculosis: Pathogenesis, protection, and control, B. R. Bloom, (ed.), American Society of Microbiology, Washington, D.C., pp. 389-415; Cheville et al., 1993, xe2x80x9cImmune responses and protection against infection and abortion in cattle experimentally vaccinated with mutant strains of Brucella abortus,xe2x80x9d American Journal of Veterinary Research 54:1,591-1,597; Chiodini, 1996. Immunology: Resistance to paratuberculosis, Veterinary Clinics of North America 12:313-342). A key component of this response is the clonal expansion of lymphocytes and the elaboration of cytokines that activate macrophages for the killing of bacteria located within the phagosomal compartment. Potent mediators of intra-phagosomal killing are reactive nitrogen intermediates (e.g., nitric oxide, NO) produced via the induction of inducible NO synthase (NOS), often as a sequalae to IFN-xcex3, TNF-xcex1, or LPS stimulation (MacMicking et al., 1997, xe2x80x9cNitric oxide and macrophage functionxe2x80x9d, Annual Reviews of Immunology, 15:323-350; Kaufmann, 1999, xe2x80x9cCell-mediated immunity: Dealing a direct blow to pathogensxe2x80x9d, Current Biology, 9:R97-99).
We have now discovered that peripheral blood mononuclear cells which have been isolated from an animal that is infected with a microbial pathogen produce nitric oxide in response to stimulation with antigens from that pathogen. Determination of nitric oxide production in cultures of peripheral blood mononuclear cells stimulated with a microbial pathogen""s antigens may thus provide a specific indication of infection of the animal by that pathogen.
In accordance with this discovery, it is an object of this invention to provide an improved method for detecting an infection in an animal by a pathogenic microorganism.
Another object of this invention is to provide a method for detecting an infection in an animal which is specific for a particular microbial pathogen.
Yet another object of the invention is to provide a method for detecting Mycobacterium or Brucella infections in an animal.
Other objects and advantages of this invention will become readily apparent from the ensuing description.